Add to boiling water for 1 minute, remove shell then fry in a little chopped garlic and butter until tender.
Seriously, when i've had em in the past i just give the line a shake and they tend to drop off. Failing that hold em just behind the head and use long forceps.
if you have hooked one and they are not just holding on. put the rod down with the cray on the floor, get your foreceps and attack the head end gently, when the cray grabs the forceps in it's pincers grab it on the carapace behind the head where the pincer arms come out.
the little bugger shouldn't be able to get you then.